When I hold my protective case in my hand it doesn't show the available empty slots, just like the ammo case and med pack. It also doesn't free the slots in my backpack. It's in my hand now shouldn't it be out of my backpack?

The issue I had was retrieving my cleaning kit that takes up 2 slots when I only had one empty slot left in my backpack. I had to place items on the ground to remove the cleaning kit to be able to use it.